Internal combustion engine



April 4, 1944. g, FLINT 2,345,569

INTERNAL COMBUSTION ENGINE Filed Dec. 5, 1941 DZU67Z7277 6%ar/ea 1 782? Patented Apr. .4, 1944 2.345.509 mama cosmus'non moms elm-res 1:. Flint, La Porte, ma, assignor to The De Luxe Products Co a corporation of In rporatiomLa Porto, IniL, diana Application December 5, 1941, Serial No. 421,800

, 5. Claims. This invention relates to improvements in internal combustion engines and more especially a multi-cylinder engine of the four-cycle type having an exhaust manifold. The invention is applicable, for example, for use in connection with such internal combustion engines now in common use on motor vehicles of various kinds.

Such an engine depends on suction means to obtain its fuel. During periods of idling, decelerating, or running under a very light load, the piston creates a vacuum on the firing stroke. When the exhaust valve opens, there is a surge of burnt gases from the exhaust manifold side of the exhaust. valve into the cylinder. The gases which have surged from the exhaust system into the cylinder are expelled again by the upward travel of the piston back through the exhaust valve. 1 However, when the exhaust valve closes, there is a slight pressure in the combustion chamber due to inertia. Almost immediately, the intake valve opens and evacuates the exhaust gas remaining in the combustion chamber. The following intake stroke, therefore, will necessarily be a mixture of 'bumt gases and fresh gases from the carburetor. The burnt gases have a debilitating effect on combustion because of the fact that the proportion of burnt gases is equal to or greater than the gas supplied by the carburetor. The principal feature of my invention is the provision of means for permitting atmospheric air to enter the engine cylinders through the exhaust manifold at light throttle settings and on deceleration. I provide an atmospheric vent on the exhaust manifold controlled by a check valve so that said valve will open when a back suction is created upon opening of the exhaust valves. As a result of this more air and less exhaust gas is drawn back into the combustion chambers and intake manifold.

It is possible to obtain better combustion conditions by the use of this device, particularly at idle and under extreme light loads. on deceleration. the engine is'freer, permitting it to decelerate more slowly, a definite economy factor. If the throttle is opened, and closed when the vehicle is traveling at a speed considerably above idle, the customary backward and forward surging of the vehicle is minimized.

The device accomplishes something which engineers have long considered desirable, scavengine the cylinders of most of the burnt gases. The device also contributes to the ease and comfort of driving an automobile. I

Other features and advantages of my invention will appear more fully as I proceed with my specification.

In that form of device embodying the features of my invention illustrated in the accompanying drawing, Fig. 1 is a view in side elevation, and Fig. 2 is a view taken as indicated by the line 2 of Fig. 1. v

As shown in the drawing, ll indicates the exhaust manifold of a conventional six-cylinder four-cycle internal combustion engine.

Attached to the manifold ill is a vent pipe ii leading to atmosphere and controlled by a very light check valve or diaphragm it mounted on the guides II, it. This valve is extremely light and may be made of a very thin metal wafer so that a very slight lowering of pressure in the exhaust manifold below atmospheric will cause it to open to vent atmospheric air into the manifold.

Over the diaphragm valve i2 on two of the guides i3, I3 I mount a cross-bar it provided with an adjustable stop screw II to limit the upper movement of the valve l2. 7

Below the valve I 2, in, the lower end of the pipe ii, I provide an auxiliary chamber ll with a restricted orifice il open to atmosphere. I have found that if this auxiliary chamber it with the small opening I! is not provided there is likely to be undesirable fluttering or'vibration of the valve l2. By providing this extra chamber this is prevented and the valve is caused to close more quickly than otherwise would be the case.

In operation, if there is any suction from the exhaust manifold by the cylinders the valve It opens sothat the contents of the exhaust manifold are diluted with air. Such dilution produces better combustion conditions in the engine at times when the same is idling, decelerating. or pulling a light load.

While I have shown and described certain embodiments of "my invention. it is to be understood that it is capable. of many modifications.

Change, therefore,v in the construction and ar-v rangement may be made without departing from the spirit and scope of the invention.

Although the invention is especially applicable for use with a multi-cylinder engine, it is obvious that it may also have utility in connection with a single cylinder engine where the latter is equipped with any kind of exhaust system such as an exhaust pipe, muiiier, or any kind of exhaust passage. In other words. if the cylinder does not exhaust directly into the atmosphere,

but into any kind of passage or chamber, there is a possibility that the pressure in such passage or chamber will fall below atomspheric, with the result that exhaust gas in such passage or chamber will be drawn back through the exhaust valve into the cylinder if at any time the pressure in the latter becomes below atmospheric when the exhaust valve is open. Consequently, if the passage or chamber is provided with a vent embodying my invention, when this occurs air will be vented into the passage so that more air and less exhaust gas will be drawn back intov the cylinder under the conditions referred to.

As stated, although the invention is applicable for use with a four-cycle engine, it also may have utility in connection with a two-cycle engine. An engine of this type may. under certain conditions, have a pressure in the cylinder below atmospheric when the exhaust valve is open. At such time any gases in the exhaust manifold, exhaust pipe, or other passage connected to the exhaust valve, will be drawn back into the cylinder. By employing my invention, a vent may be placed in the exhaust passage so that when pressure in such passage falls below atmospheric, air will be vented into the passage from the atmosphere. Consequently, there will be more air and less exhaust gas drawn back into the cylinder under the conditions above mentioned.

What I claim as new and desire to secure by Letters Patent is:

1. In combination with a multi-cylinder engine of the four-cycle type having an exhaust manifold beyond the exhaust valves of the cylinders, said manifold being under alternating pressure and vacuum adjacent the cylinder during operation of the engine; an atmospheric air vent in the manifold adjacent the cylinders; and a check valve without substantial inertia in said vent responsive to said alternating vacuum and pressure.

2. A combination as set forth in claim 1, in which the check valve comprises a very thin metal wafer.

3. A combination as set forth in claim 1, in which an auxiliary chamber is provided in the air vent outside of the check valve and said auxiliary chamber is provided with a restricted orifice to the air.

4. A combination as set forth in claim 1, in

which the check valve is a thin metal wafer and in which an auxiliary chamber is provided in the air vent outside of the check valve and said auxiliary chamber is provided with a restricted orifice to the air.

5. In combination with a multi-cylinder engine having an exhaust manifold common to a plurality of cylinders beyond the exhaust valves of the cylinders, said manifold being under alterna'ting pressure and vacuum adjacent the cylinders during operation of the engine; an atmospheric air vent in the manifold adjacent the cylinders; and a check valve without substantial inertia in said vent responsive to said alternating vacuum and pressure.

CHARLES R. FLINT. 

